1. Field of the Invention
This invention relates to wedges used by loggers in harvesting trees and in particular it relates to an improved drive head for a wedge utilized in harvesting trees.
2. Background of the Invention
Long tapered wedges are tools that have long been used as an aid to loggers in felling trees. The wedges are used to maintain the dimension of the saw kerf as the trunk of the tree is sawed and at the completion of the saw cut the wedges are used to provide a lift for directing the fall of the tree. The wedges taper from a head end (base) down to a thin edge.
Trees are harvested, that is, cut down by loggers using chain saws. The logger generally cuts a V notch into a side of the tree to provide a "hinge" for felling the tree in a desired direction. The logger then produces a saw cut through the trunk of the tree, starting on the side opposite the V notch. As the saw cut progresses through the trunk of the tree, the weight of the tree will cause a bending of the tree to collapse the kerf to bind the saw in the cut. To prevent this from happening, long tapered wedges are driven into the saw kerf to maintain the saw kerf dimension. The thin edge of the wedges are inserted into the saw kerf and large hammers, such as sledge hammers are used to forcibly drive the wedges into the kerf by impacting the head of the wedge. When the saw cut is completed, the logger may drive the wedges in further to provide a lift (i.e., tilt the tree) to direct the fall of the tree.
As previously mentioned, the wedges are driven into the saw kerf by striking (i.e. impacting) the head end of the wedge by driving tools, such as sledge-hammers. Currently, many of the wedges are produced from a plastic material. The plastic wedge is lighter, is not subject to rust and is easier to drive into the saw kerf. However, the wedges are used over and over and the repeated pounding by the hammer deforms the head of the wedge. The plastic material will not withstand the repeated pounding from the hammer and the wedge soon deteriorates.
To lengthen the useful life of the plastic wedges, metal caps or ends have been affixed to the head end of the wedge. The metal caps are of the same width as the base of the wedge. However, the full metal cap increases both the weight and cost. It is desirable to have a less heavy and less costly wedge that performs better than the heretofore old plastic wedge even though it may not perform as well as the plastic wedge with full metal cap.